The torsional resistance and lateral rigidity of a rubber crawler have great effect on the wheel detachment prevention performance (coming-off preventing performance) and durability. However, the circumferential rigidity of the rubber crawler is increased simultaneously, and such increased bending rigidity presents a significant problem for a moving device.
The technique for improving the torsional resistance and lateral rigidity is shown in the patent document 1, which discloses a structure having, in addition to main cords, two bias cord plies embedded extending toward opposite sides in a lateral directions as reinforcing layers and layered one over the other. When such a rubber crawler is used, the torsional rigidity and the lateral rigidity become favorable to achieve excellent wheel detachment prevention performance (coming-off preventing performance) and durability. However, at the same time, the rigidity in the circumferential direction becomes larger, and the crawler does not get wound around the sprocket and rotates loosely, which may ultimately cause a problem of larger power loss in a machine to which the rubber crawler is mounted. Further, when the rubber crawler is wound around the sprocket, the trailing performance with respect to the sprocket is lost, which causes tooth jumping (tooth skip phenomenon) and finally breaking of driving projection.
Meanwhile, there has been proposed a rubber crawler having laterally mutually-opposite bias cords butt-jointed to each other as reinforcing layer in order to achieve excellent torsional rigidity and lateral rigidity of the coreless rubber crawler (see Patent document 2). However, in this state, it is difficult to achieve enough high lateral rigidity of the crawler and the rubber crawler may be buckled laterally.    Patent document 1: Japanese Patent Application Laid-Open (JP-A) No. 2002-178965    Patent document 2: Japanese Patent Application Laid-Open (JP-A) No. 2001-010556